For All The World
by Bounemr
Summary: Marinette's twin brother takes the Miraculous off her hands for a night to give her a chance to dress up and impress Adrien. Things spiral.


Marinette was freaking out. Thomas didn't understand what the fuss was about, but the school dance was obviously important to his sister ( _Well, Adrien is important to her._ ) so he did his best to help her get ready. "Mari, breathe for a moment, will you?"

Marinette paused her frantic rummaging through her closet only long enough to give him a penetrating glare. "I _can't_ Tommy, I have to impress Adrien tonight!"

"Okay, then." He stood from his place on the chaise, and walked over to her. "How about this, then. What's so difficult about your dress decision?"

"Everything." Marinette threw a pink dress directly into his face, but Thomas was mostly sure she wasn't actually aiming.

"Do you know what shoes you're wearing?"

"No! I need to pick a dress first!"

"Okay, well, here." Thomas gently moved Marinette away from the closet and sorted through it himself. "You look great in green. This will knock his socks off." He made his pick and handed it to Marinette. "Now, pick your everything else."

"Oh… okay. This will work, thank you."

"My pleasure." Thomas walked over and plopped back down on the chaise.

Not a minute later, he was getting up again. "Tommy, which necklace should I wear? I like the gold with the dress but with my earrings…"

He saw what she meant. "No, you're right, you can't wear gold with earrings that have a silver base."

Marinette pouted. "Help me find another necklace?"

"Nah, just wear that and pick some nice earrings that will blow Adrien away. I'll wear the Miraculous."

Marinette looked anxiously over at Tikki, who frowned. "Excuse me, Thomas, but what do you mean she should wear 'nice' earrings?"

Thomas shrugged and reached around Marinette to root through her jewelry box. "What? The Miraculous are literally just black circles. She's got these really pretty dangly ones… Ah, right here." He picked them up and held them to his sister's ears. "Don't these work perfectly?"

Marinette let out an almost dreamy sigh. Mostly resigned, though. "They do. But I can't just take off the Miraculous."

"You aren't. I'll wear them."

"You'll wear earrings to the school dance?"

"I _do_ have my ears pierced. Everyone at school knows I wear earrings. And besides. Black circles actually do work with black suit."

"But I'm Ladybug. It'd be irresponsible."

"I can handle being on call for one night, Mari. You deserve to enjoy yourself."

"So do you."

"I'm not trying to impress a crush, nor have I been routinely going out saving the city now, have I? I'm only going to hang out with our friends. Maybe laugh at how hopeless you are."

"You're the worst." Marinette whined, but she took the earrings out of his hands and looked over at Tikki. "Is that allowed?"

Tikki pouted, still a little offended at Thomas' comment about the Miraculous not being pretty. "Technically, he can use my power, but…"

"But?" Thomas asked.

"Well, it's a little unprecedented!"

"You cannot tell me that the Miraculous was never shared in over five thousand years."

"I know it seems unlikely but it's only ever happened a couple times!"

"Look, I can fight. I train with Mari all the time, right? I just want to give her a good night off."

Tikki crossed her arms. The two stared each other down for a long moment. "Fine." Tikki conceded. "But Marinette is still my Ladybug."

"Wouldn't dream otherwise, Tikki."

Marinette sighed and took off the earrings, handing them to Thomas. "Oh, thank you Tikki! And you, Tommy. What would I do without you?"

"Have terribly clashing accessories, probably." He smirked and put them on, examining himself in the mirror. "Wow, I actually look good in these. Maybe I should get bigger earrings."

"You're just not used to seeing yourself all dressed up, mister 'graphic tees and blue jeans'."

"Someone in this family has to have no fashion sense."

"Oh really? Because you were just telling me how good I looked in green and how I can't wear silver earrings with a gold necklace."

"What can I say? Even a blind squirrel finds nuts sometimes."

Marinette turned to him and started tying his bowtie, which had been hanging loosely around his neck. "You should dress up more." She winked. "The girls will be all over you."

He groaned. "If that does happen, do you think Alya will protect me?"

"Definitely. She'll steal you for herself."

"Please, she's as gay as I am."

Marinette laughed. "A fair point. Thanks for helping."

"Well, if I didn't intervene we'd never get there."

"Rude!" She slapped his shoulder and led the way downstairs.

* * *

Thomas should have expected the akuma. Aside from the obvious fact that they were at an event deemed important by large swaths of the school population, it was also the night, the only night, that he was wearing the Miraculous instead of his sister. Irony practically dictated that someone was upset – by some punch spilled on a dress, or a love interest dancing with someone else, or any number of other things – just because that meant _he_ had to be the one to play hero. _He_ had to fight the akuma, sow confusion because the Parisian people would only wonder what's up with this new Ladybug and what happened to the one they love?

The answer: she was a little tied up. And by tied up, Thomas meant that she was currently serving as the spool for a very, very long thread. _Figures it'd be a seamstress akuma too. That's her expertise._

The night had started out nice. He arrived with Marinette, found Alya, Nino, and Adrien, and relaxed a little. Well, he did. Marinette only got tense. She stuttered and blushed until Alya pulled her away to go to the restroom. That was about the point where some student began bawling because her dress was ripped. Thomas was fairly certain that it was no one's fault in particular, but he recognized the signs enough to realize then that he wasn't getting away transformation-free.

He had initially tried to find Marinette, to give her the earrings, but he couldn't reach her before she was captured. She gave him a single, sharp look, telling him to transform.

So, he stole into the school, finding the way out and out from the akuma's gaze, until he was alone in a dark room with no one to witness what was undoubtedly going to be a very embarrassing event. "Tikki, sorry, but transform me."

He stretched, and sprinted back to the courtyard. _This is actually surprisingly comfortable. Almost makes up for leaving literally nothing to the imagination._

 _Speaking of leaving nothing to the imagination._ He paused in the doorway, having a hard time swallowing the lump in his throat. The akuma was still there, thankfully, but so was Chat Noir. _What the heck am I supposed to tell him?_

Thomas grabbed his yo-yo uncertainly, and joined the fray.

"Ah, My Lady! How kind of you to- wait, w-" The rest of Chat Noir's sentence was cut off when Thomas grabbed his arm and yanked him close, narrowly saving Chat Noir from one of the akuma's attacks.

"I understand that this is weird, Chat Noir, but let's talk after the fight, maybe?"

"Fine." Chat Noir's voice was a little cold, a little gruff, a lot confused. Mostly confused.

Thomas sighed and looked around. And noticed that he was only inches from Chat Noir. He felt his face flush and backed away quickly, muttering an apology. That in itself only seemed to make Chat Noir more confused. He tilted his head and his cat ears swiveled around towards him. _Oh crap, he's cute._

"Duck!" Thomas dropped to the floor at Chat Noir's word, spinning low to the ground to face the akuma. _Don't get distracted._ He flicked the yo-yo into his other hand, so that he had the string between his fists, skirted out from under the thread in the akuma's control, and charged.

The akuma, luckily, didn't seem to expect that approach, and hesitated long enough to attack for him to get most of the way to his goal. A hop, skip, and a jump later, he was standing at the akuma's feet. She held an arm out to order one of the threads, but Thomas caught it in his yo-yo string, wrapping it once to keep it trapped in the string. Then, he danced over and wrapped up her other arm too, in effective handcuffs.

He called to Chat Noir, who dove in, but the akuma managed to kick Thomas hard in the chest, sending him flying. Chat Noir changed course, reaching Thomas in two bounds and catching him, though the impact knocked Chat right off his feet and on his back. Chat Noir let out a pained chuckle. "Falling for me already, Ladybug?"

Thomas knew his face had to be as red as his suit when he scrambled off of Chat Noir. _Oh, god, why does he have to flirt, too? As if this wasn't awkward enough._

And Chat Noir had the gall to _wink_ at him. "Where'd you learn to tie people up like that, anyway?"

"Kill me." Thomas hid his face in his hands. Chat Noir downright cackled.

Thankfully, the impact of the kick only knocked the yo-yo out of his hand, and not off his finger, so it was still attached to him by the wire. The akuma had already disentangled herself, so all Thomas had to do was flick it back to his hand.

"Seriously, though," Chat said, "that was pretty cool. Good to know you can fight, too."

"Duh." He rolled his eyes, recovering slightly from his embarrassment. "Ladybug wouldn't leave you with someone who can't fight."

"Who are you, anyway?"

Thomas deflected an attack with his yo-yo. "Not the time, Chat Noir."

"So formal. The other Ladybug calls me 'Kitty'."

"You enjoy being called a kitty, then?"

"Only by Ladybugs." He winked again. Thomas found his cheeks burning again.

 _If that's how it's going to be, it'll be less awkward if I play along. I hope._ "If you insist. I'll call you whatever you want me to."

He hoped his smile was more flirty than mortified.

Luckily, he didn't have to see Chat Noir's reaction, because he was suddenly very busy avoiding akuma attacks.

Thomas had seen his sister use her powers and heard her describe them more than enough times to pull off a relatively seamless execution of all three. With Chat Noir's help, the akuma was taken down and cleansed, and the world was returned to the way it was.

Except for Chat Noir standing there with his arms crossed, tapping his foot, looking at Thomas like some fresh scrap of meat.

 _Okay, maybe that's exaggeration. But I do not like that look._ His earrings beeped. Two minutes to go. "Sorry, got to run."

"Not so fast. You owe me an explanation."

Thomas was torn between spilling everything and just booking it, but when he looked away from Chat Noir, he caught his sister's gaze, who seemed to find the whole situation just far too funny for his own good. Alya was also nearby, predictably, and already making her way towards him. "Okay fast version." He leaned in close to Chat's ear so that no one would overhear him. "I know Ladybug as a civilian. She had something very important to do so she left me with the earrings tonight." He backed off, knowing his cheeks were red but ultimately more focused on absconding as quickly as humanly possible. "Your Ladybug will see you tomorrow, okay? She can explain if that isn't enough."

Chat Noir furrowed his brow, Alya was getting dangerously close, already yelling for just a moment of his time. Thomas turned tail and booked it. Over his shoulder, he called back, "Bye, Kitten!"

* * *

"Oh my god." Thomas buried his head into his arms. His sister's hand was on his back, rubbing it gently. "Oh my god how could you let me do that? I don't think I could have been any more awkward than that."

"It wasn't as bad as you think."

"I'm not going to stop blushing until I die."

"Chat is regularly that awkward. You're okay."

"I'm going to die."

"No you aren't."

"Yes I am, let me die."

"Tommy, get up."

"No. I'm going to sit here until the bittersweet embrace of death claims me."

"Up." He felt arms slip under his own, and Marinette picked him up from under his shoulders, lifting him to his feet.

"I hate how strong you are, sometimes."

"Tough. Tell me honestly, Thomas. Do you have a crush on my cat?"

Thomas groaned. " _Marinette_ , don't even."

She giggled. "Fine. Do you have a crush on Chat Noir."

"How dare you insinuate such."

"Really? Because you were flirting quite a bit, there."

" _He_ was flirting. If I did it it's only because it would be awkward otherwise."

"Mhmm. Good then. So you won't mind taking tonight's patrol."

Thomas choked. "What? No! Tikki sai-"

"I think you've proven yourself capable. Besides, I have something _very important_ to do."

"Tikki doesn't want me using the Miraculous. She made herself clear. Last night was the exception."

Marinette looked over at Tikki with pleading eyes. Tikki herself huffed, crossing her arms and turning away. "You weren't… a _bad_ keeper. And it would make things easier for Marinette if you split duties."

"Tikki!"

"Ha!" Marinette pumped her fist in the air. "Besides, Tommy, don't you want to see your kitten again?"

" _Your_ kitten. I only called him that because he… sort of… asked me to." His words went up at the end as he trailed off, like a question.

"I think you should be the one to explain to him why I wasn't there."

"I already told him you'd tell him tonight."

"Tell him I decided he deserves the explanation from you, and that I'll talk to him during the next patrol." Thomas crossed his arms, pouting. "It was your idea."

"Yes, but I didn't think I'd _actually_ have to transform."

Marinette smirked. "Oh! Maybe I should send Alya a tip to your route! She'd be delighted to catch the mysterious new Ladybug with _plenty_ of time to talk."

"I am not the new Ladybug! I don't want to be a hero!"

Tikki floated over, taking Marinette's side (of course) and no longer showing any sign of friction between them (because she wasn't admitting she was wrong, probably). "Neither did Marinette."

"That is…" Thomas stood for a few seconds, shaking his finger at Tikki. "A fair and valid point but I am not just taking over as Ladybug for you!"

"I'm not asking you to. I'll still have the earrings most of the time, but this way I can have the occasional day off."

"I don't have your experience. Fighting akuma is a lot different than mma training with you."

"Then I guess we'll have to split it more evenly so you can get used to it, huh?"

Thomas sighed, defeated. "Why are you doing this to me? My own sister. I thought you loved me."

"I do. I also happen to think that you around Chat acting like me around Adrien is beyond hilarious and kind of adorable."

* * *

 _If only Paris knew the real Ladybug._ Thomas sighed, clad in red and black and perched on a high alcove on the Eiffel Tower. _They'd know she's a dirty villain. No hero would do this to me._

 _Paris is pretty from up here, though, isn't it?_

"Good evening, Ladybug!"

 _Oh, great._ "Hey, Kitten."

Chat Noir paused, standing next to him. "You said my- that is… hmm." Thomas glanced up to see Chat furrowing his brow, staring intensely at the support beam.

"You're wondering why the real Ladybug isn't here, since I told you she would be."

"I wouldn't say 'real'. You're a Ladybug too, that was clear enough from yesterday."

Thomas just shrugged and swung his feet.

"So why are you here?"

Thomas couldn't resist muttering. "Because she hates me."

"Excuse me?"

"Nothing. She just thought that you deserved a better chat with me. She'll definitely be back for your next patrol, so you can talk things through with her, too."

Chat Noir hummed low in his throat. "Alright, then." He dropped down, sitting close. Thomas would have backed away, but he was already pressed against a vertical beam. Chat was so close they were nearly, very nearly, touching. "Let's chat."

Thomas tore his eyes away from Chat Noir and focused on the cityscape. "Uh, okay. I'm sure you have questions."

"Yes. Firstly, who are you?"

"You know I can't answer that." Thomas closed his eyes. "I know Ladybug. She trusts me. If I told you who I was, that would compromise her identity, and she doesn't want that."

Chat Noir was quiet for a moment. "But you don't care?"

"Not really. I care about her, and so I guess I care about this by proxy or something, but if it were just me no I couldn't care less." He leaned forward, his elbows on his knees. "God, Tikki's probably going to chew me out for even saying that."

"Why take the Miraculous?"

"It was… okay it wasn't _exactly_ her idea. It was mine, but I just wanted to give her a night off. She had this event she really wanted to go to, and she really wanted to impress this guy, so I told her I'd take the Ladybug duty just for the night. You know, so she didn't have as much to worry about. I wanted her to have fun."

He looked up at Chat Noir. In the other hero's green eyes was such a slew of emotions, Thomas couldn't begin to decipher them. "Did she? Have fun, I mean."

Thomas rolled his eyes. "Yeah. A lot of it at my expense, but yeah."

"Really? She saw the fight, then?"

"Oh yeah, she saw it. And she'll never let me forget it." He ran a hand over his face.

"You did well."

"It's not the combat that was embarrassing, dude."

Chat Noir tilted his head, his brow furrowed for a fraction of a second, and then his eyes widened. "Oh! Oh. Sorry."

Thomas groaned. "Don't worry about it. She would have found some way to ridicule me anyway."

"Do you want me to stop with the…"

"Nah." Thomas waved him off. "It's cool. Not going to lie, though, I was surprised when you started flirting."

To his satisfaction, Chat Noir actually blushed at that. He rubbed his neck, looking away. "Ah, well… that's… what I'm used to?"

"Mhmm." Thomas, feeling daring, smirked and leaned close.

Chat coughed awkwardly and scooted a tiny distance away. "So, uh, how often will I have you instead of the other Ladybug?"

Thomas chuckled. "You'd have to ask her. I'm just her lackey in this department. And she was the chosen one, so naturally she's going to have the Miraculous for the most part. I'm just here to make her life easier."

Chat's demeanor changed again, more cocky, forward. He sat up straighter, leaned towards Thomas, smirked. "You make my life easier, too."

Thomas arched an eyebrow. "Really? How?"

Chat nodded enthusiastically. "Oh, yes, much easier. On the eyes." He winked and pointed finger guns, and Thomas blushed despite himself. _I hate you so much right now, Mari._

He hummed, proud at how well he controlled his features, save the blush. "Are you like this with Ladybug?" Chat reeled back, partially or maybe faking being offended. "Because if so, she's one lucky bug." _Why do I only dig myself deeper?_

Chat's grin seemed larger than the tower they sat on. "Okay, I've decided. I like you."

"You sure? There's still time to hate me."

"Never. Come on, we need to patrol."

He stood, stretched, and offered a hand. Thomas took it, allowing Chat to pull him to his feet.

* * *

Despite Marinette's later insistence that she had not sent Alya the patrol route, Thomas and Chat Noir found her waiting on a bridge over the Seine. One of many total, and one of two that they'd be using that night. _There is absolutely no chance that this is a coincidence._

The bridge was, of course, a trap. While Thomas _may_ have been able to grapple to something on the opposite side and swing over in one leap, Chat Noir would have a hard time vaulting so far without using the bridge. It was effectively a choke point, and Alya clearly knew that.

Thomas supposed he could have just ignored her, but the arrangement meant there was no way he could miss her, nor her, him. And she had been watching the rooftops like a hawk, and called out to them as soon as they were visible. "Ladybug! Chat Noir! A moment, please?"

Thomas was tempted to fly right on by, but Chat flipped and landed neatly right in front of her, so he figured he was out of luck. He dropped down from the building he was on and made his way carefully over.

"The mysterious hero! Just who I wanted to see." She called, not giving him the chance to stay in the background.

He approached slowly nonetheless. "How did you know we'd be here?"

Alya rolled her eyes. "I knew about this route for weeks. I was waiting for something big before catching Ladybug and Chat Noir here." She winked. "My gut was right. Something big did come."

Thomas frowned, furrowed his brow, opened his mouth to say something, closed it again.

"So, what do we call you?"

Thomas exchanged a glance with Chat Noir. "Uh… Ladybug?"

"Come on, now, we need a brand. The new hero needs a new name."

"But… I'm Ladybug, though. Spots and everything. I'm not a different hero. Earrings, see?"

Alya frowned. "Okay, so that's the same Miraculous that Ladybug uses?"

"Yeah."

"Why do you have it? What happened to Ladybug?"

"Nothing! I was just… doing something nice for her. Giving her a night off. I didn't want it to become a thing, you know? But now she wants me to get used to this or something."

"So… you're her sidekick? She's training you to take the Miraculous when she retires."

"Sure. I'm her sidekick."

She turned her piercing gaze to Chat. "Do you have a sidekick?"

"No." Thomas tensed and felt his face heat up when Chat slung an arm casually around his shoulders. "I need to make sure Baby Bug here is all trained up before worrying about anything like that. Since Ladybug obviously can't be out here with him, I get to teach him the field stuff."

Thomas looked at Chat in exasperation and disbelief. "Baby Bug?"

"Well, you're the new one."

"I'm the same age as her!"

"Are you?" Alya asked. "And how old is that?"

Thomas just glared at her. "If you let that be my official nickname I will never speak to you, ever."

Alya rolled her eyes. "Fine. That'll just be your 'My Lady', then."

"He's not calling me that, either."

Chat held back his laughter. "Oh, I am definitely calling you that."

Thomas shrugged Chat's arm off his shoulder and crossed his arms. He did realize, then, that Alya was recording the entire conversation, and he'd be seen pouting on the internet for all the world, but he couldn't find it in himself to care at that moment. _Marinette is never going to let me hear the end of this._

* * *

It took even less time than Thomas thought for Marinette to tease him about the "baby bug" incident. That is to say, she was teasingly calling him baby bug the moment he arrived on the balcony.

Apparently, Alya was streaming live.

"No, really Tommy, you should see some of these comments. People already ship you with Chat."

"You liar."

"I'm serious! Look!"

They sat together on her bed as she shoved her phone into his hands. The comments were more or less a mix of "I don't trust him, where's the real Ladybug?", theories about his relationship with Ladybug (everything from married to twins, but Thomas kind of expected that. The twin theory wasn't taken any more seriously than any other, so he didn't worry), commentary on Alya's questions and recommendations for things to ask in future interviews, "baby bug, oh my freaking god", and "look at the way he blushes when Chat touches him!".

So, no, Marinette wasn't lying when she said people shipped him and Chat Noir. Thomas just hoped to every god that could even possibly exist that Chat never saw it.

Marinette, always the helpful sister, snickered. "You know Chat follows the Ladyblog too."

Thomas just sighed, handed her phone back, and peered over the edge of her bed. "Do you think, if I fall on my head, this could kill me?"

"That's enough of that, Tommy. I'll take the earrings, go to your own bed." Thomas handed her the Miraculous and inched closer to the side of her bed. "And take the ladder, please."

He sighed, and climbed down. After saying goodnight, he ventured off to his own room to ruminate on his embarrassments.


End file.
